text: def decode(s):
      n = len(s)
      if n == 0:
          return ""
      l, r = "", ""
      for i in range(n%2, n, 2):
          l = s[i] + l
          r = r + s[i+1]
      return l + (s[0] if n%2 else "") + r
  
  n = int(input())
  s = input()
  r = decode(s)
  print(r)
  